Yeardley was a University of Virginia lacrosse player who was murdered by her ex- boyfriend, George Huguely V, in May 2010.

Couric says Sharon, Lexie and Yeardley used to call themselves the “three musketeers” after the girls’ father John died of prostate cancer in 2003.

Lexie, who is getting married at the end of the month, told Couric that her sister would have been her maid of honor.

“They’ve had to deal with a lot of loss, and I think it’s very difficult for them to move forward, but they’re doing the best they can,” Couric says.

Last month, Huguely was sentenced to 23 years in prison for beating Love to death. During the trial, facts surfaced that he had tried to choke Love while they were dating.

Women who are choked by their partners are five times more likely to be murdered by the same partner, Couric says.

Dating violence will be the focus of the show.

“We really wanted to use what happened to Yeardley as a cautionary tale for other young women and even some young men out there who might be at risk for dating violence which is so prominent in our culture right now,” she says.

Below is a video preview of the “Katie” interview of Yeardley Love’s mother and sister:

One in three college students say they have been in an abusive relationship, and one in 10 high school students say they have been physically harmed by a boy or girl.

Couric says she thinks digital devices have made it easier for harassment and violence to occur in relationships.

“You can constantly be in touch with someone, but that also means you can constantly be on top of them, harass them and really exhibit